Dutch type designer and technical font whiz kid. Started the LettError virtual type foundry with Erik van Blokland, with whom he worked at MetaDesign.
Fame came with the release of Beowolf (co-designed with van Blokland), a font whose ragged edges shift randomly each time you print the font. His oeuvre includes many typefaces that are deliberately low-tech in appearance. Most of his fonts are published by FontFont.
He is a key developer on the Robofog project with Erik and Petr van Blokland. He also leads a drive to get the font tool developer community to use XML as a font interchange format; his own TTX program is an excellent start.